JPS59226621A - Circuit breaker - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a circuit breaker having an overcurrent tripping device.

[Technical background of the invention and its problems]

Conventional circuit breakers perform full-wave rectification of the output of a current transformer connected to the main circuit, and use this rectified output as a signal for detecting overcurrent, as well as energizing the trip device and overcurrent detection circuit. It is also designed to be used. in this case,
In order to keep the energizing voltage of the overcurrent detection circuit constant, the full-wave rectified output of the current transformer is converted into a DC voltage by a smoothing circuit using a capacitor, a resistor, a constant voltage diode, and the like. The terminal voltage of this voltage regulator diode is used as a power source for the overcurrent detection circuit. For example, this voltage is 15
Volts are required, so the turns ratio of the current transformer must be large to obtain this voltage. Therefore, when the main circuit's current increases, the output voltage of the current transformer becomes higher than safe, and the voltage drop across the resistor connected in series with the voltage regulator diode increases.

Therefore, the load on the current transformer is large, power consumption increases, and the current transformer itself must be large. For example, when using a circuit breaker for wiring, there is not enough space for a current transformer, so a sufficiently large current transformer cannot be used, and the linearity of current detection in the main circuit deteriorates in the high current region. do. Also, since the series circuit of a constant voltage diode and a resistor is used as a power supply circuit for a tripping device,
Large-sized devices with high power consumption are used, which is an obstacle to making the device more compact. In addition, if a large current flows in the main circuit due to a short-circuit failure in the load, overvoltage will occur in the output winding of the current transformer, so a high voltage surge absorber is required between the output windings. The capacitors in the rectifier circuit are also required to have a high withstand voltage, which increases the cost of the device.

Furthermore, since the detection output of the current transformer is used both as a current detection signal and as a power source for the circuit breaker, changes in the characteristics of the voltage regulator diode due to temperature appear as fluctuations in the detection signal, which may affect the accuracy of the circuit breaker. There was a drawback that the value decreased.

[Purpose of the invention]

The purpose of this invention is to be able to detect current with high linearity over a wide range of current changes in the main circuit, to prevent the detection voltage from becoming an overvoltage even in the large current region of the main circuit, and to be compact and economical. To provide a circuit breaker.

[Summary of the invention]

According to this invention, the above object is to detect the current in the low current region of the main circuit by a current transformer, and to detect the current in the large current region by a current detector using a Hall element attached to the gap of the magnetic ring. This is accomplished by configuring the circuit breaker to do so.

[Embodiments of the invention]

The present invention will be described in detail below with reference to the drawings of embodiments. In FIG. 1, a load 4 is connected to an AC single-phase power source 1 via a breaker contact 2 and a main circuit 3. As shown in FIG. This breaker contact 2 connects the base to the OR circuit 3 via the resistor 18.
It is driven by a tripping coil 15 that is energized by turning on the transistor 14 connected to the transistor 6, and is controlled to open and close.

The main circuit 8 has eight output windings 16-1.16-2゜1.
The primary conductors of current transformer 16 with 6-8 are coupled. In the main circuit s, there is also a jacket insulation material bus 1 of the current sensor 17.
7-1 is connected. The current sensor 17 is connected to this bus 17-
1 and a Hall element 17-2 with a magnetic ring.

The terminals of the first output winding 16-1 are connected to four diodes 5
-1.5-2.5-8.5-4 terminals of the second output winding 16-2 connected to the AC input terminal of the full-wave rectifier 5 are connected to four diodes 18-1. 18-2゜18-8.
It is connected to the AC input terminal of the full-wave rectifier 18 consisting of 18-4. A terminal of the eighth output winding 16-8 is connected to an AC input terminal of a full-wave rectifier 19 consisting of four diodes 19-1.19-2.19-8.19-4.

A capacitor 20 and a constant voltage diode 55 are connected in parallel between the DC output terminals of the full-wave rectifier 5, and a series circuit consisting of a resistor 21 and a diode 22-3 in the selection circuit 22 is also connected in parallel. A positive terminal of the rectifier 5 is connected to one end of a resistor 81-1 via a diode 22-1, and a negative terminal is connected to a negative line N.

A capacitor 28 is connected between the DC output terminals of the rectifier 18, and a series circuit of this capacitor 2814, a resistor 24, and a constant voltage diode 25 is connected in parallel.
The positive terminal of is connected to one end of the tripping coil 15, and the connection point between the resistor 24 and the constant voltage diode 26 is connected to the positive line P.

On the other hand, the negative terminal is connected to the negative line N.

A capacitor 26 is connected between the DC output terminals of the rectifier 19, and a resistor 27. A series circuit consisting of a constant voltage diode 28 is connected. The resistors 29-1 and 29-2 of the constant current circuit 29A are connected in series between the terminals of the constant voltage diode 28, and the power supply terminal of the operational amplifier 29-8 is further connected. The non-inverting input end of the operational amplifier 29-8 is connected to the connection point of the resistors 29-1 and 29-2, and the inverting input end is connected to the sliding end of the variable resistor 29-4. The output terminal of the operational amplifier 29-3 is connected to the 10 input terminal of the Hall element 17-2, and the - input terminal is connected to the L output terminal of the variable resistor 29-4. The H output terminal of the variable resistor 29-4 is connected to one power supply terminal of the operational amplifier 29-8.

One output terminal of the Hall element 17-2 is commonly connected to one end of the resistor 80-1.80-2 in the full-wave rectifier circuit 80, and the other output terminal is connected to the negative line N. It is commonly connected to one end of the resistors 80-5, 1-11 and 81-4. Resistor 80-1. Between the other ends of 80-2, resistor 8
0-8.80-8 are connected in series, resistors 80-1 and 80
-8 is connected to the inverting input terminal of the operational amplifier 30-4.The non-inverting input terminal of this operational amplifier 80-4 is connected to the other end of the resistor 80-5, and the output terminal is connected to the diode 80.
-6 to the connection point of resistors 80-8 and 80-8, and further via diode 80-7 to the inverting input terminal (two connected).

The connection point of the resistor 80-2.80-8 is the operational amplifier 80-
The inverting input end of the amplifier 80-10 is connected to the other end of the resistor 80-11. Its output terminal is connected to its inverting input terminal via a resistor 80-9,
Further, it is connected to a non-inverting input terminal of an operational amplifier 81-2 via a resistor 81-1 in the amplifier circuit 81. This amplifier 8
The inverting input terminal of resistor 81-2 is connected to the other terminal of resistor 81-4. Its output terminal is connected to the inverting input terminal via a resistor 81-8, and is further connected to a diode 22-2. It is connected to the non-inverting input terminal of the operational amplifier 82-4 via the resistor 82-1 of the amplifier circuit 82A. The inverting input terminal of the amplifier 82-4 is connected to the resistor 82.
-2 to the negative line N, and is also connected to the resistor 82-8
Connected to the output end via.

The output terminal of this operational amplifier 82-4 is connected to the operational amplifier 88-
2.84-2.85-2, and one input terminal of 2.85-6. The positive and negative power supply terminals of each amplifier 88-2.84-2.35-2 are connected to a positive line P and a negative line N, respectively. A variable resistor 88- is further connected between the positive and negative lines P and N.
1.84-1.85-1 are connected in parallel. Each sliding end C of the variable resistor 88-1.84-1.85-1 is connected to the amplifier 8.
8-2.84-2.85-2, respectively. The output terminal of the amplifier 33-2 is directly connected to the OR circuit 86.
is connected to the first input terminal of the. Here, variable resistor 88
-1. Amplifier 88-2 constitutes instantaneous characteristic circuit 88.

The variable resistor 84-1 and the amplifier 84-2 constitute a short time characteristic circuit 84, and the output terminal of the amplifier 84-2 is connected to the resistor 84-8.
connected to one end of the The other end of the resistor 84-8 is connected to the negative line N via the capacitor 84-4, and further connected to the non-inverting input end of the operational amplifier 34-6. This amplifier 8
The inverting input end of 4-6 is connected to the sliding end of variable resistor 84-5, and the fixed ends H and L are connected to positive and negative power lines P and N, respectively. The output terminal of the amplifier 84-6 is connected to the second output terminal of the OR circuit 36.
connected to the input end of the

Variable resistor 85-1. The operational amplifier a5-2 constitutes a long time characteristic circuit 35, and the output terminal of the amplifier 35-2 is connected to a resistor 8.
5-8 to the base of transistor 85-5. The collector of the transistor 35-5 is the resistor 35-4.
through the positive line P, and the emitter is connected to the negative line N
connected directly to.

The output end of the resistor 85-6 is connected to one end of the resistor 35-7, and the other end is connected to the FET 85-8. It is connected to one end of a capacitor 85-10, and further connected to an input end of an amplifier 85-12. The other input terminal of amplifier 85-12 is negative line N.
connected to. The gate of FET 85-8 is connected to the collector of transistor 85-5, and the other end is connected to resistor 35-9.
connected to one end of the The other end of capacitor 85-10 is connected to one end of resistor 85-11. Resistance 85-9.85
The other end of -11 is commonly connected to the positive power supply end of amplifier 85-12. The output terminal of the amplifier 85-12 is an operational amplifier 86.
-14 is connected to the non-inverting input terminal. This amplifier 85-
14 is connected to the sliding end C of the variable resistor 85-18, and its fixed ends H, L and the power supply terminal of the amplifier 85-14 are connected to the positive and negative lines P, N, respectively. The output terminal of the amplifier 85-14 is connected to the third input terminal (
Two are connected. The output terminal of the OR circuit 86 is connected to the pace of the transistor 14 via the resistor 18, the emitter is connected to the negative line N, and the collector is connected via the tripping coil 15 to the positive side output terminal of the full-wave rectifier 18.

In the circuit breaker configured as described above, a single-phase AC negative
Power is supplied to 4. First output winding 1 of current transformer 16
The detection output generated at 6-1 is converted into direct current by the full-wave rectifier 5, supplied to the resistor 21, and converted into a voltage signal. The capacitor 2° performs peak charging of the signal generated in the output winding 16-1, and at the same time performs noise removal. The constant voltage diode 55 is connected to the output winding 16-1 when a large current flows through the main circuit 8 due to a short-circuit failure in the negative direction 4, etc.
It has the effect of suppressing overvoltage that occurs in゛The output signal of the second output winding 16-2 is converted into a p direct current by the full wave rectifier 18, and is supplied to the constant voltage diode 25 via the resistor 24, so that a constant direct current voltage is negative line P,
Supplied between N.

The DC voltage obtained between the terminals of the series circuit consisting of the constant voltage diode 25 and the resistor 24 is supplied to the tripping coil 15 via the transistor 514.

When a large current flows between the terminals of the constant voltage diode 25 in the main circuit 8 due to a short-circuit failure, etc., the output winding 16-
It has the effect of suppressing the overvoltage that occurs in 2. Capacitor 28 is for smoothing the output of full-wave rectifier 18 and removing noise.

The constant voltage obtained between the terminals of the constant voltage diode 25 is used as a control voltage for the entire circuit, including a full-wave rectifier circuit 80, an amplifier circuit 81 . Amplification circuit 82. Instantaneous characteristic circuit 88. Short time circuit 8
4. and is supplied to the long time characteristic circuit 85.

The output of the eighth output winding 16-8 is rectified by a full-wave rectifier 19, and a constant DC voltage is obtained between the terminals of the constant voltage diode 28. The capacitor 26 is for smoothing the signal generated at the output of the winding 6-8 and removing noise. The constant voltage diode 28 suppresses overvoltage generated in the output winding 16-8 when a large current is generated in the main circuit 8 due to a short-circuit failure or the like.

The constant voltage generated between the terminals of the constant voltage diode 28 is used as a control power source for the constant current circuit 29.

In the constant current circuit 29, a constant current determined by the voltage divided by the resistors 29-1 and 29-2 and the voltage dividing ratio of the variable resistor 29-4 is obtained from the amplifier 29-8, and this output is A current is supplied as a control current to the Hall element 17-2 attached to the air gap of the magnetic ring of the current sensor 17. Here, the magnetic field generated in the ship 17-1 by the current flowing through the main circuit 2 is focused by the magnetic ring, and the Hall element 17
-2, an output voltage proportional to the strength of this magnetic field is generated in the Hall element 17-2, and this is supplied to the full-wave rectifier circuit 80. When the output voltage of the Hall element 17-2 is ten, the amplifier 80-4 operates as an inverting amplifier, the diode 80-6 is in a short-circuited state, and the diode 80-7 is in a short-circuited state.
It becomes a cutoff state. An output voltage on one side determined by the ratio of resistors ao-i and ao-8 is generated on the anode side of diode 80-6. On the other hand, the + side human input signal is supplied to the amplifier 80-10 via the resistor 3o-2. The signal inverted to one side by amplifier 30-4 is transferred to resistor 80- by amplifier 80-10.
Amplifier a
Appears at the output end of o-to. Further, the child side input signal supplied via the resistor 80-2 is inverted by the ratio of the resistors 80-2 and 80-9 in the amplifier 80-10, and is sent as a negative side signal to the output terminal of the amplifier 30-10. appear. Therefore, the output of the amplifier 80-10 is the sum of the input signal inverted to one side by the amplifier 30-4 and the input signal supplied via the resistor 80-2. The value of each resistor is determined so that a + side output is generated.

When the output voltage of the Hall element 17-2 is on one side, the amplifier 8
Since 0-4 operates as an inverting amplifier, its output is inverted, diode 80-6 is cut off, and diode 8
0-7 are short-circuited. In this way, amplifier 80
-4 is short-circuited by a diode 80-7, and no signal is supplied to the inverting input terminal of the amplifier 80-10 via the resistor 80-8. Further, by the signal supplied through the resistor 30-2, a voltage inverted to the positive side determined by the ratio of the resistors 80-2, 80-9 is obtained at the output terminal of the amplifier 30-10.

The output of the full-wave rectifier circuit 80 obtained in this manner is supplied to the non-inverting input terminal of the amplifier 31-2 via the resistor 81-1. This amplifier 31-2 operates as a non-inverting amplifier and provides an output voltage determined by the ratio of resistors 81-8 and 81-4. The amplification factor of this amplifier 81-2 is such that the output winding 1
Resistor 21 and diode 22-8 detected by 6-1
is set so that the signal voltage across both ends of the current sensor 17 is higher than the output voltage of the amplifier 81-2 according to the output signal of the Hall element 17-2 of the current sensor 17. Therefore, the current of the main circuit 8 is 100 OA. In the following region, the signal voltage across the resistor 21 and the diode 22-3 is
1 becomes an input signal to the amplifier 32. Here, the forward voltage drop of the diode 22-1 is
Since the voltage detected by the resistor 21 becomes the input signal voltage of the amplifier circuit 32, the voltage detected by the resistor 21 becomes the input signal voltage of the amplifier circuit 32. Voltage is diode 22-2
The signal is supplied to the amplifier circuit 82 via. This amplifier circuit 82
The output level is adjusted to match the signal level of the trip characteristic circuit connected to the subsequent stage. The output voltage of the amplifier circuit 32 is supplied to each characteristic circuit 38-85. The variable resistor 88-1 in the instantaneous characteristic circuit 88 is set to have instantaneous characteristics with respect to the current value. The reference voltage set in this way is supplied to the inverting input terminal of amplifier 88-2. The variable resistor 84-1 is used for current setting with short-time characteristics, and the obtained reference voltage is supplied to the inverting input terminal of the amplifier 84-2. The variable resistor 84-5 is for time setting of short-time characteristics, and the obtained reference voltage is applied to the amplifier 34.
-6 is supplied to the inverting input terminal.

The variable resistor 85-1 is used for setting a current with long-time characteristics, and the obtained reference voltage is supplied to the inverting input terminal of the amplifier 85-2. The variable resistor 85-18 is used to set the time characteristic of the long time characteristic, and the obtained reference voltage is supplied to the inverting input terminal of the amplifier 84-14.

When the current value of the main circuit 8 becomes abnormal, for example exceeding 100 OA, the output voltage of the amplifier 82 exceeds the set reference voltage of the instantaneous characteristic circuit 88, an output is generated from the amplifier 38-2, and the OR circuit 36 ．． A trip signal is supplied to the base of transistor 14 via resistor 18, transistor 14 is turned on, trip coil 15 is energized, and contact 2 is opened.

Further, when the output voltage of the amplifier 82 exceeds the reference voltage of the short time characteristic circuit 34, an output is generated from the amplifier 84-2, and the resistor 84-8. The signal is supplied to a time constant circuit made up of a capacitor 34-4. When the terminal voltage of the capacitor 34-4 exceeds the reference voltage provided by the variable resistor 84-5, the amplifier 84-6
An output is produced and the trip coil 15 is energized.

When the output voltage of the amplifier 32 exceeds the reference voltage of the long time characteristic circuit 85, the output voltage from the amplifier 85-2 to the transistor 85-5
An output is supplied to the base of the transistor 85-5, and the transistor 85-5 is turned on. As a result, the collector potential of the transistor 86-6 decreases, and the FF) T 35-8 turns OFF.

As a result, the output signal of the 2 meter quantity 85-6 is transmitted to the amplifier 85-1.
It starts to be integrated at 2. The capacitor 135-10 is charged and the output voltage of the amplifier 85-12 is changed to the variable resistor 85-1.
When the reference voltage set in 8 is exceeded, the amplifier 85-14
An output is generated in the OR circuit 86, and the tripping coil 15 is energized.

In this way, the eight output windings 16-1.16-2°16
-8 current transformer 16 and a sensor 17 using a Hall element 17-2 attached to the gap of the magnetic ring, the current detection of the main circuit 3 is carried out in the low current region by the output winding 16-2.
1 output, the large current region is carried out using the Hall element 17-2 attached to the gap of the magnetic ring. Since the Hall element 17-2 has an air gap in its magnetic ring, it does not become saturated even with a large current, so that linearity of current detection can be achieved over a wide range. That is, since the linearity of current detection by the output winding 16-1 does not need to be wide, there is no need to make the iron core of the current transformer 16 large. Furthermore, the number of turns of the output winding can be reduced, and the burden on the secondary side of the current transformer 16 can also be reduced.

The output voltage of the output winding 16-2, 16-8 is used as a power source for each characteristic circuit 80 to 85, so it may be saturated as the output of the current transformer 16, and the iron core is small and the secondary winding is You can also do less. Even if a large current due to ζ2 flows in the main circuit due to a short circuit accident, the current transformer 16 is saturated, so the overvoltage on the output side is reduced.

Moreover, the output voltage of the Hall element 17-2 attached to the gap of the magnetic ring will not become overvoltage due to a large current, and the circuit configuration will be simplified. Also, resistor 21. Constant voltage diode 2
The rated power of 5,28.55 may be small, and the circuit configuration becomes compact.

Further, the control current to the Hall element 17-2 attached to the gap of the magnetic ring is supplied from the output winding 16-8, and the output voltage of the Hall element 17-2 is supplied to the downstream of the output winding 16-2. Since the insulation between the input and output of the Hall element 17-2 is made of a good quality material, it is possible to reliably prevent potentials from coming into contact with each other, and stable operation can be achieved. Also, 0 volts of the current detection signal and O of the circuit power supply
Since the volt level is the same, highly accurate operation is possible regardless of fluctuations in the power supply voltage.

Pushpu 17 mounted on printed board 17-7 and with outer insulation
-1 top (: indicates the installed state. Here, terminal 1
A control current is supplied to 7-8.17-4, and terminal 17-
The Hall element output voltage is taken out from 5.17-6. FIG. 2(b) is a cross-sectional view of the current sensor 17 shown in FIG. Figure 8 (,
). This is done based on the hole created by the current transformer in the air gap in the main circuit.

FIG. 4 shows the structure of another embodiment of the invention.

This embodiment is an application of the embodiment shown in FIG. 1 to an eight-phase circuit. Here, a current transformer 87.8 is added to the current transformer 16 in FIG.
9 was added, and the R-phase current of the main circuit was detected by the first output winding 16-1 of the current transformer 16 connected to the R-phase, and the S-phase current and T-phase current were similarly provided. Output winding 87-1.8
9-1, respectively. The detected output is passed through a four-phase full-wave rectifier 5a (=
It is rectified by resistor 21. The diode 22-8+ is converted into a pressure signal and supplied to the selection circuit 22a.

The output voltage of the output winding 16-2.87-2.89-2 is
It is rectified by a four-phase full-wave rectifier 18a consisting of diodes 18-1 and 18-8'Ak, and is supplied to a constant voltage diode 25ζ2 through a resistor 24, and between its terminals (to obtain a control DC voltage. The R-phase detection output of the winding 16-8 is rectified by the full-wave rectifier 19, and a constant voltage is obtained across the constant voltage diode 28 via the resistor 27.

The voltage between the terminals of this constant voltage diode 28 is the voltage between the terminals of the constant current circuit 2.
9, and a control current is supplied to the Hall element 17-2 attached to the air gap of the magnetic ring. The output voltage of the Hall element 17-2 attached to the gap of the magnetic ring is rectified by the full-wave rectifier circuit 8o, and is supplied to the amplifier circuit 82 as an R-phase current detection signal.

Similarly, the S-phase and T-phase currents are detected by the Hall elements 88-2, 40-2 attached to the air gaps of the magnetic rings, respectively, and rectified by the full-wave rectifier circuits 46, 58, and the amplifiers 47-2, 40-2.
After being amplified at 54, the signal is supplied to an amplification circuit 82. The remaining circuit configuration and operation are the same as in FIG.

In this way, in the case of an 8-phase circuit, current transformers 16 and 87.89 each having three output windings and Hall elements 17-2.88-2.40-2 installed in the air gap of the magnetic ring are used. As a result, the current flowing through the main circuit 8a is dividedly detected depending on its magnitude, and linearity over a wide range can be obtained. others,
Since the operation of this circuit is basically the same as that shown in FIG. 1, no further detailed explanation is considered necessary.

FIG. 5 shows the configuration of the eighth embodiment, in which the current transformer 1 of FIG.
The first output winding of 6 is connected to two windings 16-1a, 16-1
The only difference is that it has a differential configuration according to b.

The winding directions of these two windings 16-1a and 16-1b are opposite to each other, and a current corresponding to the difference in the number of turns between them is supplied to the resistor 21 and the diode 22-8. In this case, since the output windings 16-1a and 16-1b are of a differential type, it is only necessary to obtain a certain level of output difference;
-The number of turns of 1b can be reduced. There is no need to increase the number of turns even when the output signal value is small. Because it is a differential system, overvoltage will not occur even if a large current flows through the main circuit. Therefore, resistance 21. Diode 22-8. The rating of the constant voltage diode 55 (the force can be reduced and the shape can also be reduced).

FIG. 6 shows the configuration of yet another embodiment. This is an application of the single-phase circuit shown in Fig. 5 to an eight-phase circuit, in which the first output windings 16-1, 87-1
．． 89-1 has a differential configuration.

In this case as well, the overall configuration can be made compact.

FIG. 7 shows the configuration of yet another embodiment. In this configuration,
Full-wave rectifier 5° in the embodiment of FIG. 1 Eighth output winding 16-8. Capacitor 20. Constant voltage diode 55. Resistance 21. Diode 22-8 is omitted. As a result, a relatively small value of the current in the main circuit 3 is detected by detecting the terminal voltage of the resistor 24 on the output side of the full-wave rectifier 18.

Therefore, the terminal voltage of the resistor 24 is 11-1°1, respectively.
1-3 to the respective non-inverting operational amplifiers 11-5.

A resistor 11-4 is coupled to the inverting input terminal, and is connected between the output end of the amplifier 11-5 and the inverting input terminal.

The output of amplifier 11-5 is supplied to amplifier circuit 82 via diode 22-1. Other configurations.

The operation is the same as in FIG. 1, and the explanation will be omitted.

As in this embodiment, the current detection signal in the low current region, the control power source, and the power supply to the tripping coil 15 are obtained from the detection output of the first output winding 16-1 of the current transformer 16. , and even if the detection output of the second output winding 16-2 is used as a control current source to the Hall element 17-2 attached to the air gap of the magnetic ring, substantially the same effect as in the embodiment of FIG. 1 can be obtained. is obtained.

FIG. 8 shows the configuration of yet another embodiment of the invention. 7th
In the embodiment shown in the figure, the second output winding 16-2 is omitted in FIG. This is how it was done. The other configurations and operations are the same as those of the embodiment shown in FIG. 7, and their explanations will be omitted.

FIGS. 8(b) and 8(c) are output characteristic diagrams of a Hall element attached to a gap in a magnetic ring, showing another embodiment of this description. When detecting spot flow using a Hall element installed in the air gap of a magnetic ring, the cross-sectional area of the iron core of the magnetic ring is made smaller than that shown in Fig. 3 (,), and is approximately 115 or less. This is a case where a straight line region with a gradient tan θ2 in the section (2) is used. That is, even when the main circuit current is between 0 and 1, there is a first linear region with a gradient tan θ1, but since the cross-sectional area of the magnetic ring is small, the linear region from 0 to 1 is extremely narrow. When the main circuit current increases further, that is, the section from 2 to 2 is becoming saturated, but because there is a gap in the magnetic ring, it is not completely saturated, and as the main circuit current increases, As shown in FIG. 3(b), the output voltage of the Hall element increases even though the slope is tanθ2 and the bias B is present. That is, E=(tanθ
, )I+B...il) The output voltage E of the Hall element is obtained. The main circuit current section uses the output signal of the current transformer, and the section from the main circuit current section to I3 uses the output signal of the Hall element attached to the gap of the magnetic ring.

By providing a bias C in the amplifier 81 of FIG. 1 in place of B in the first equation, and further changing the amplification degree of the amplifier 81, tanf)2
Adjust so that tan θ becomes 1 instead. That is, l1i=
(tan θ,) I+C (2) is connected at the output IR point of the current transformer. In this case, the cross-sectional area of the magnetic ring core can be reduced, making it extremely compact. Furthermore, the current sensor can be constructed at a lower cost.

〔Effect of the invention〕

As described above, according to the present invention, current detection is carried out by the first output winding of the current transformer in the region where the current in the main circuit is small, and current detection is carried out by the magnetic ring in the region where the current in the main circuit is large. Since the current sensor configured using a Hall element attached to the air gap is made to share the load, even if the current in the main circuit increases, the output of the current sensor maintains linearity. Therefore, the effective detection range for overcurrent is widened, and even in large current areas such as short-circuit fault current, even if the content of DC component is large, saturation does not occur because the magnetic ring has a gap, and it can be installed in a gap. Hall element allows accurate current detection. The accuracy of overcurrent detection has also been improved, and since the linearity range is wide, the adjustable range can also be widened.

On the other hand, the range of current detection by a current transformer does not need to be wide, and the iron core of the current transformer can be made smaller and the number of turns of the secondary winding can be reduced, making the current transformer more compact and preventing short circuit failures. Even when a large current flows through the circuit, due to saturation of the current transformer,
Overvoltage is suppressed, the rated power and size of electronic components connected to the secondary side of the current transformer are reduced, and the entire circuit becomes compact. Furthermore, since the O volt line of the current detection signal and the O volt line of the power supply can be made the same, malfunctions due to fluctuations in the power supply can be prevented, and the performance of long time characteristic circuits that particularly require precision is improved. In this way, the number of ampere frames of the circuit breaker can be minimized, making standardization easier. Moreover, a highly reliable, compact, and economically efficient circuit breaker can be obtained.

[Brief explanation of the drawing]

Fig. 1 is a circuit configuration diagram of an embodiment of the present invention, Fig. 2 is a diagram showing an example of a specific configuration of the current sensor in Fig. 1, *a
The figure is an explanatory diagram of a current sensor, and FIGS. 4 to 8 are circuit configuration diagrams of different embodiments of the present invention. 1... Power supply, 2... Breaker contact, 8... Main circuit, 4... Load, 5.18.19... Full wave rectifier, 2
2.22a... Selection circuit, 15... Trip coil, 16... Current transformer, 17-2... Hall element, 17
-10... Magnetic ring with air gap, 29... Constant current circuit, 30... Full wave rectifier circuit, 81, 82... Amplifying circuit, 88... Instantaneous characteristic circuit, 84... Short time limit Characteristic circuit, 85...Long time characteristic circuit, 86...08 circuit.

Claims (6)

[Claims] (1) A first current detector including a current transformer that detects current in the low current region of the main circuit, and a magnetic ring that detects current in the main circuit in a larger current region than the first current detector. An overcurrent tripping device including a second current detector configured using a Hall element installed in an air gap; and means for supplying the output of the current transformer as a control current source for the element. (2) The current transformer has a first output winding that provides a first current detector output, and a second output winding that is used as a control power source for the overcurrent tripping device and as an excitation power source for the tripping coil. 2. A circuit breaker according to claim 1, comprising a wire and an eighth output winding used as a control current source for the Hall element. (3) The current transformers include first and second current transformers that are differentially connected to each other.
A circuit breaker according to any one of claims 1 and 12, having a second output winding. (4) The main circuit is a multi-phase circuit, the current transformers and Hall elements are provided according to the number of phases of the multi-phase circuit, and each control current source is configured to be supplied independently from each current transformer. A circuit breaker according to any one of claims 1 to 8. (5) The first current detector includes a first current detector. a current transformer having a second output winding; a first rectifier connected between the first output winding; and a first resistor and a constant current transformer connected between the output of the first rectifier. a series circuit consisting of a voltage circuit; means for applying the voltage across the terminals of the first resistor as a first current detection signal; means for applying the output voltage of the constant voltage circuit as a control power source for the overcurrent tripping circuit; the second current detector is connected between the second output winding of the current transformer; Claim 1, comprising: a second rectifier having a second rectifier; and means for supplying the output of the second rectifier to a Hall element as a control current.
A circuit breaker as described in Section. (6) The first current detector includes a series circuit consisting of a current transformer having one output winding, a resistor and a constant voltage circuit connected between the output windings, and a terminal of the resistor. means for providing the voltage across the current as the first current detection signal,
The circuit breaker according to claim 1, wherein the second current detector has means for supplying a control current from the constant voltage circuit to the Hall element.